What You Need To Know About UV Light For Plants?

UV light has the ability to destroy harmful microorganisms, particularly when the wavelengths are shorter than 300 nm. 

Not only that, but UV light can increase your plants’ resistance to bacteria, insects, and fungus.

Grow plants indoors without any UV exposure, and you'll lack all of these benefits. 

Choosing a best UV light for plants is important.

Ultraviolet light, or UV light, is part of the rainbow, just not the visible part. We measure light by its wavelength, a measurement known as a  nanometer (nm). The visible spectrum of light falls between 400 nm to 700 nm. Just outside the violet end of the spectrum begins the ultraviolet category, with a wavelength from 10 nm to 400 nm. While the human eye can’t pick up these waves lengths, but many other creatures, including plants, use it to survive.

When it comes to cannabis, harnessing some UV light may even improve your harvest.

UV light can also promote faster germination when starting seeds. They strengthen the plant and prepare it for higher light intensities. 

It reduces the “shock” time of the seedlings while also speeding up germination.

Yes, UV has benefits for plant growth, but it can still cause damage to plants and humans if not used properly.

Do not expect to enhance your plant growth by going out and purchasing a sun tanning lamp. Sun tanning lamps provide a lot of UV and human skin can only be exposed to them for short periods of time. Exposing plants to that much UV can quickly kill them.

Growers should provide their plants with a full quality spectrum which emits the right amount of UV. That full spectrum light should mimic natural sunlight to make the plants feel as if they are being grown outdoors.

Futur Vert HortiUV LED 30W UV 385NM Bar

It produces short and stout plants if you use this product for the veg stage of the plant. It is because of the light’s intensity that the grow light produces.

This light penetrates very well through the canopy and permits the little growth to advance and help bush the plant out.

Overall, this product is highly recommendable. It has a super nice light and gives you very good yields for the price.

• Larger size spreads of light, better than more compact LED lights


• Weight makes the product easier to hang


• Ten band light spectrum provides excellent attention to growth stages


• Durable construction allows the light to be used for a very long time


• Modular design allows for an easy upgrade


• Penetrates plant’s canopy effectively


• Comes with power cords and hanging equipment


• Bright light


• Affordable


• Well-built design

ECO Farm ECOM 30W UV & IR Supplemental Lighting Bar

It has been a pleasure running the 240 since flowers are dense and frosty, and smell much better than when grown under HPS.

My fellow indoor growers say that their vegetation growth doubled within just the first two weeks of changing from HPS to this LED.

It has no problems with any over-heating because it keeps the area at around 65 degrees Fahrenheit all the time.

Overall, this is an excellent product because of its good design and strong cables.

ECO Farm Supplemental Grow Light is best with high quality.

• 7-pound weight makes moving light a breeze


• Designed to optimize the cross-coverage process in areas that contain more than four plants


• Can penetrate up to 60 inches past the plant canopy


• Lack of ballast simplifies installation


• Comes with a power cord and hanging equipment


• 8-band genuine light spectrum


• Comes with Zener protection to maximize life when diodes may blow over time


• Covers over six square feet


• Bright light


• Does not require a ballast


• Doesn’t generate much heat

Most of the evidence suggests that UV-A exposure isn't tied to DNA damage in plants. Not a surprising fact considering plants are exposed to high levels of low-intensity UV-A in their natural environment. Generally speaking, the UV-A included in most grow room lights won't cause any damage to your harvest, and at least in the case of cannabis, might improve THC and CBD content if introduced correctly.

(If you are just starting out with grow room lights, this is a great introduction to indoor grow lights)

In short diffused doses, there is nothing wrong with a little UV-A light. However, over time or if exposed to intense bursts of UV-A light, it may trigger the development of skin cancer. In particular, researchers link UV-A to melanoma, the deadliest type of skin cancer. Unlike other forms of UV light, UV-A isn’t filtered-out by glass windows. Which is why you have faded curtains and aging artwork. It is also the spectrum behind your wrinkles and age spots.

The second most common UV wavelength to reach the earth from the sun is UV-B. Its electromagnetic wavelengths range from 314 to 280 nm. It’s interesting because it triggers oxygen creation and the regeneration of the ozone layer. It makes up the remaining 1.3 percent of UV light reaching the earth’s surface.

In the right dose, introduction a little bit of UV-B light into your indoor grow room can be a good thing. Ultraviolet light of the B variety encourages plants to produce their own natural sunscreen. These sunscreens vary from one species to another but include trichome, terpene, and color development. The UV-B spectrum also offers a bit of natural protection against fungal infection and unwanted pests.

Humans have a love-hate relationship with this middle spectrum of UV light. On the one hand it's the type which triggers Vitamin-D production, but on the other hand it does damage skin, and if left unchecked can cause skin cancer. We need it, but we also need to take precautions against too much of it. Most sunscreens on the market include protection from harmful UV-B rays, as well as grow room glasses.

UV-C light accounts for a full zero percent of UV light reaching the earth’s surface. While UV-C light is now artificially made, the ozone layer completely absorbs this wavelength, which means no UV-C light penetrates through the earth's atmosphere. It ranges in wavelength from 280 to 0 nm.

This is where the truth about UV light in the grow room gets a bit confusing. Out in the great outdoors, plants are not naturally exposed to UV-C lighting, because it doesn’t permeate through the ozone layer. They don’t need it to grow, and it can be one of the most damaging wavelengths of light to expose your plants too. Many growers don't realize that UV-C does damage to the plants DNA.

But, with that said, UV-C lighting wands are often sold as a hand-held tool designed to sanitize the workroom from microorganisms. These wands borrow from UV-C technology used to sterilize water in the backcountry. Ultimately, UV-C will kill everything with too much exposure, including your plants. If you do decide to use a UV-C wand in your grow room, cover up and protect yourself and your plants from excessive exposure. Your plants certainly do not need UV-C to grow, and your grow lights don't produce it.

Of course you should! Despite the downside of using UVs incorrectly in the grow room, there’s no question that UV light offers a slew of benefits that can help your indoor plants thrive.

Whether you are using ultraviolet light for a large, commercial operations or for smaller, private use, adding a UV wavelength to your grow light will boost the quality of your yields like nutrients never could.

• Your plants’ specific light needs: Not all plants produce resin, and not all resin is as useful as you’d hope. If you’re going to use UVs, make sure your plants can actually benefit from them. If they can, you’ll want to also figure the height, power, and position of UVs around your plants in order to safely produce resin.


• Height and Space Limitations: You’ll want to hang UVs at the same height as your other lights. Hanging UVs too close to your plants can bleach them, so make sure you have room to hang UVs at a safe distance.


• Safety precautions: Long-term exposure to UV radiation without any form of protection can be dangerous for humans and plants alike. You’ll want to limit the exposure time and intensity of UVs for your plants as you can bleach or burn them from these hyper-intense wavelengths. Glasses and long sleeves are also helpful if you’re spending lots of time exposed to ultraviolet light.


• Cost: You should keep costs in mind when you are deciding whether or not to use UV light in your grow room. 
  
  
  
  • LED grow lights have a harder time incorporating UVs into their systems, which makes LEDs with a uv wavelength are a little more expensive than other lights. 
  
  
  • UV-T5s are the cheaper route and are great if you’re already using HIDs and T5 grow lights.
  
  
  
  

There has been some talk about when using UV light is actually effective. Some growers say you shouldn't use it during veg, as it won't contribute much and will just be a waste of money.

A common theme we hear is "don't invest in the veg, invest in the flower". But, if you don't invest in the veg, how is your plant going to be capable of producing a frutiful harvest?

That's why we recommend using UV lighting full cycle if you can - from seed to harvest. By giving UV light to your plants during propagation & early veg, they will develop thicker cuticles, faster metabolism, and just be overall stronger and healthier.

There is no question that all of this adds up to a plant that can yield heavier, and more potent. So, rather than adding in high doses of UV light at key points, we recommend using low doses of UV light over the entire life. This is safer, and more effective.